Funds are requested for purchasing an analytical ultracentrifuge, which will in turn support a new initiative in bioorganic and biophysical chemistry centered in the Chemistry Department at CWRU. This initiative features seven major users with expertise in biological macromolecules and supramolecular assemblies. Presently, there are no analytical ultracentrifuges in the state of Ohio. The requested instrument will clearly enhance research prowess and productivity on the NIH-supported projects of the major users. It will also stimulate interactions and collaborations among faculty and students in the Chemistry Department, the Medical School, and the College of Engineering at CWRU as well as nearby institutions, such as Cleveland State University and the Cleveland Clinic Foundation. Dr. Barkley (PI) is experienced in analytical ultracentrifugation, particularly in applications to protein-protein interactions. The major users represent individuals (Lee, Zagorski, Jamieson) and groups of individuals (Barkley, Surewicz, Shainoff, Qin). Dr. Lee is expert on proteolytic enzymes. Drs. Zagorski and Surewicz are expert on protein folding and misfolding. Dr. Surewicz also represents six users from the Medical School. Dr. Jamieson is expert on mucins. Dr. Shainoff is expert on blood clotting proteins and represents two users from Cleveland State University. Dr. Jun Qin is expert on protein structure determination and represents eight users from the Cleveland Clinic Foundation. The major users will bring fundamental studies of protein-protein and protein-nucleic acid interactions as well as interactions of proteins with prosthetic groups and ligands to bear on key structure-function questions in a wide range of biological systems. The synergism among their research groups spawned by-the requested instrument will greatly facilitate progress on their research projects. The requested analytical ultracentrifuge will be used to measure molecular weights as well as macromolecular association constants and stoichiometry. Also requested is a printer for hard copy output and a density meter for buoyancy factor determination. The equipment will be housed in a newly renovated laboratory of the Cleveland Center for Structural Biology (CCSB), which is the Major Analytical Instrument Facility (MAIF) in the Chemistry Department.